#include <stdio.h>
int main()
{
    int n = 3;
    while (n)
    {
        printf("%2d is true\n", n--); // 3 2 1
    }
    printf("%2d is false\n", n); // 0
    n = -3;
    while (n)
    {
        printf("%2d is true\n", n++); //-3 -2 -1
    }
    printf("%2d is false\n", n); // 0
    return 0;
}